Cracking oil



Patented July 26, 1932 UNITED STATES BENJAMIN L. sou'rnrza, or PITTSBURGH, AND JOHN w. GREENE, or wrimNsnuiie,

PENNSYLVANIA, ASSIGNORS T GULF REFINING SYLVANIA, A. CORPORATION OF TEXAS onAoxr Ci' on),

No Drawing.

This invention relates to cracking oil; and it comprises an improvement in methods of cracking oils containing sulfur wherein such an oil is passed through tubular heaters as ,6 Iiquid or as vapor and is cracked, heating being in transit and the vapors of cracked products being subsequently condensed in the usual condensers, said improvement residing in supplying a minor amount of air to the flowing oil, the amount being about that corresponding to the H S which would otherwise appear in the gases passing such a condenser; all as more fully hereinafter set forth and as claimed.

Many petroleum oils contain sulfur which is converted into a highly corrosive form in cracking for the production of gasoline. The form in which it exists when corrosion occurs is unknown but a measure of the corrosive properties of the cracked products can be ascertained by observation of the H 3 equivalent of the gases leaving the final condenser. The percentage of H S by volume in these final gases is usually rather small but in a general way variations in the amount correspond to variations in the observed corrosion. In the ordinary tubular cracking units which heat oil in transit, either as vapor or liquid, and discharge it into chambers of one kind or another, much of the corrosion observed is found in apparatus located between the tubular heating unit and the final condenser. Because of this corrosion it has been found expedient in many vapors comin cases to use apparatus composed of, or lined w th, non-corrodlble materials in lieu of the ordinar steel construction. This is a source of considerable expense and inconvenience Application filed May 24,

COMPANY, or

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19am. serial No. 455,454. p y A air is too small to produce any substantial combustion or heatingeflect; "We ordinari ly supply enough air to give oxygen equi'v' alent to about two molecules for every molecule of H 'Swhich would otherwise occur in the gases passing the cdndenser 01', stated in and her way, about ten parts of air by wolurne for each volume of H sw Th'iresult is that the'H S is greatly reducedin" the effliient gases and the corrosionin the cracking apparatus ismi-nimized'; the tubes, chambers and condensers do not corrode t'o 'a'nylsubstantial extent.

. a typical embodiment of our invention, operating with the usual tubecracking appa ratus, consisting of a'tubularheater, a separating chamber to "which the heater discharges, a dephlegmator and a condenser, and operating under a pressure from 100 to 200 pounds, with introduction of oil to the tubes at a pump pressure of 350 pounds, the system is run under normal conditions and the volume of H 8 in the gases passing the condenser is observed. Air is then introduced with the oil at the entrance of the cracking tube usually in the proportion of about ten volumes of air for each volume of H S observed. More than 15 volumes of air to every volume of HS which would otherwisebeproduced is seldom necessary. The air is compressed to a compression slightly higher than the pump pressure of the oil entering the tubes and the air is metered through an 0rifice meter in the calculated amount. Of course a Venturi tube or a Pitot tube can be used.

The air may be metered before going to the air compressor. The ratio given refers to air and exit gases under like pressure.

The exact amount of air to be used in any case can be determined by the amount of H S found in the gases coming from the final condenser, the object being to obviate as nearly as may be appearance of H 8 or sulfur in forms equivalent to H S.

Due to the fact that a very small quantity of air is needed it is possible that the action is one of changing the nature of the sulfur compounds, or some of them, in the oil so that H 8 itself is never formed. It may be that sulfids are converted to sulfoxids or sulfones. The latter are known to be quite stable. No S0 appears as a result of the use of air and there is no reason for assumin that H S is first formed and is then oxidize The air seems to be more eflective when introduced at the entrance of the cracking tube rather than when distributed at several points along the length of the tube.

What we claim is 1-. In processes of heating and cracking corrosive oil while in transit with subsequent condemnation of vapors the method of reducing corrosion which comprises determining the quantity of H S normally present in the vapors, and supplying air to the flowing oil in minimum amount suflicient to prevent appearance of H S in the gases leaving the final condenser.

2. In the process of heating and cracking corrosive oil while in transit, the method of reducing corrosion of the apparatus which comprises determining the quantity of H S normally generated, and supplying air to the oil while in transit in the ratio of not substantially less than 10 nor more than 15 volwoes of air to every volume of hydrogen sulfid which would normally be produced in the cracking of the oil.

In testimony whereof, we have hereunto aflix'ed our signatures.

BENJAMIN L. SOUTHER. JOHN W. GREENE.

CERTIFICATE OF CORRECTION.

Patent No. 1,869,028. July 26, I932.

BENJAMIN L. SOUTHER ET AL.

it is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2 line 12, claim 1, for "condemnation" read condensation; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of October, A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents.

fones. The latter are known to be quite stable. No S0 appears as a result of the use of air and there is no reason for assumin that H S is first formed and is then oxidize The air seems to be more eflective when introduced at the entrance of the cracking tube rather than when distributed at several points along the length of the tube.

What we claim is 1-. In processes of heating and cracking corrosive oil while in transit with subsequent condemnation of vapors the method of reducing corrosion which comprises determining the quantity of H S normally present in the vapors, and supplying air to the flowing oil in minimum amount suflicient to prevent appearance of H S in the gases leaving the final condenser.

2. In the process of heating and cracking corrosive oil while in transit, the method of reducing corrosion of the apparatus which comprises determining the quantity of H S normally generated, and supplying air to the oil while in transit in the ratio of not substantially less than 10 nor more than 15 volwoes of air to every volume of hydrogen sulfid which would normally be produced in the cracking of the oil.

In testimony whereof, we have hereunto aflix'ed our signatures.

BENJAMIN L. SOUTHER. JOHN W. GREENE.

CERTIFICATE OF CORRECTION.

Patent No. 1,869,028. July 26, I932.

BENJAMIN L. SOUTHER ET AL.

it is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2 line 12, claim 1, for "condemnation" read condensation; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of October, A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

